Wired or Wireless Time Machine Backup to Hard Disk Connected to Another Mac on Your Local Network

Ever since I decided to start using Time Machine it has been bugging me that I could not figure out how to back up my my iMac to an attached FireWire HDD and my PowerBook to the the same HDD over the Network. Of course I could buy TimeCapsule, but I wanted to make it work with what I had. You can find tips to active an attached HDD on an Airport Extreme or other network location (e.g., here, or here), but I was not interested in that. Also, there are some solutions out there for using Leopard Server (e.g., here, )

The solution presented below requires just one one desktop Mac with an external HDD (I use firewire, but I would expect USB to work as well), one Mac laptop, and any local wireless network (I use my ATT U-verse modem/router). I learnt that I wanted to do is possible from this Macworld article, alas, it does not give detailed instructions. read on to find out how it works.


Your main computer, e.g., an iMac (Server) is connected to your router which in turn is connected to the internet, e.g., via a DSL modem. (connection to the internet is not required for this to work). Also connected to the iMac is the (local) Time Machine backup hard drive. If you have a PowerMac, this could also be another internal hard drive. a separate post explains how to duplicate your Time Machine backup to a remote backup hard drive. It can easily be connected to the first one via Firewire. Also connected to the router is your laptop, e.g., a PowerBook or MacBook, or any other computer on your network such as a Mac Mini that you want to backup (Client).

For the first backup it is highly recommended to have both the server and the client connected via Ethernet cable to the the router to speed up the backup. Subsequent backups can be performed wirelessly since they tend to me much smaller. Also note that the first backup cannot be done by connecting the backup drive directly via firewire since on a directly connected drive the backup is located in a folder, while on a networked drive the backup is located in a disk image. For an alternate solution aiming to avoid this, see here (I have not tried this).

Here are the steps needed:



  1. Turn on Sharing on the Server: Go to the sharing pane in System Preferences and click on File Sharing. Note that you do not need to define special shares in the boxes on the right. In this example, the Server is called “Big Apple”.



  3. All remaining steps are done on the Client. In the example, the Client is called “FruitBar”. Open the Finder. The Server should show up under the shared category as shown below.


    Finder with Share


  5. If you click on the Server in the sidebar, Leopard will automatically connect to it if you have previously connected to it. This is shown below. If you have never connected to the Server, skip to step 4.


    Here, we are connected to the Server as a user (“Toby”, in this example) which is convenient for accessing personal documents, but right now you want to be connected as an administrator. To connect as a different user–an administrator in this case–click the disconnect button.

    Finder already connected


  7. The Finder changes as shown below. To connect, click the “Connect As…” button.


    Finder disconnected


  9. A dialog window will pop up. Enter the administrator user name (“Admin”, in this example) and password for the server as shown below. You don’t need to save the password in the keychain.



    6. Once connected as an Admin, you’ll see certain folders and hard drives on the Server as shown below. Note that when you were connected as a non-administrative user, you could not see the connected hard drives.


    7. The screenshot below shows the remote Time Machine hard disk selected. Double click on that disk to connect to it.


    8. Now go to the Time Machine preference pane. When you turn on time machine, the window below pops up. The remote hard disk is automatically selected.



    9. After clicking “Use for Backup” the below dialog appears. Enter your Admin user name and password. This will allow to mount the remote hard drive when it is available on the network. This is really convenient because will not have to enter the credentials again.


    10. When complete, Time Machine starts preparing for the first backup. Before it starts, you may want to edit the options (see below). I exclude applications since those are either on the Leopard install disk, or in a folder where I keep all my Installers/Disk Images. I also exclude downloads and mail downloads since downloads I want to keep are moved out of those locations. I used this opportunity to switch all my browsers to save downloads in the download folder; until now I had some files downloaded to the desktop. Finally, system files and applications can be excluded by selecting the System folder on the Machintosh HD folder and the selecting All.


    11. Once options are complete, Time Machine will count down for the first backup (“13 seconds to go” in the image below):


    12. Then it prepares for the backup


    13. Once the backup starts, the finder will automatically mount the remote backup location if it isn’t mounted already. Note that not the remote drive (Time Machine Local) is mounted, but a sparse disk image which is located on the remote drive.


    14. During the initial backup, the following progress window appears. In ?subsequent backups, this will not appear.



    15. When complete, the remote disk image will automatically be unmounted.

    16. Every hour, time machine will try to connect to the remote disk and perform a backup. If the drive cannot be mounted, e.g., because the computer is used away from home, Time Machine will delay the backup until the next time when a network connection to the drive can be established.

    Sometimes it will show an error message. This is not to worry about. Next time you’re connected to the network, simply click on the Time MAchine Icon in the menubar and select “Back up now”.


4 Responses to Wired or Wireless Time Machine Backup to Hard Disk Connected to Another Mac on Your Local Network

Leave a Reply

Your email address will not be published. Required fields are marked *